Thermostatic control of vessels subjected to heating

ABSTRACT

A sensor is borne by a head extended by a metallic arm which passes through the flame of the burner. To avoid exaggerated heating effect on the capillary tube communicating the sensor to the thermostatic control, it is surrounded by a sheath of highly conductive metal. This sheath ends in a tube of the same metal which can be extended by a radiator. In this way, the conductive sheath constitutes a heat pump removing heat to the outside. The head can be protected on the inside by a layer of insulating material. The device is particularly useful for domestic gas cookers.

United States Patent [191 de Gouville June 28, 1974 THERMOSTATIC CONTROL OF VESSELS SUBJECTED TO HEATING [75] Inventor: Jean-Bemard de Gouville, Veigne pres Montbazon, France [22] Filed: Jan. 31, 1972 [21] Appl. No.2 221,932

[30] Foreign Application Priority Data Feb. 2, 1971 France 71.3496

[56] References Cited UNITED STATES PATENTS 2,336,092 Grooms 73/3684 2,366,091 12/1944 Eskin 73/3684 2,386,164 10/1945 Hurley 73/3684 X 2,495,086 1/1950 Anderson 126/374 X 3,135,118 2/1964 Zlobin 73/368 3,213,922 10/1965 Weber 73/3684 X 3,266,318 8/1966 Abajian et al. 73/368 3,632,040 l/1972 de Gouville 236/20 Primary Examiner-Richard C. Queisser Assistant Examiner-Daniel M. Yasich Attorney, Agent, or Firm-Eric l-l. Waters [57] ABSTRACT A sensor is borne by a head extended by a metallic arm which passes through the flame of the burner. To avoid exaggerated heating effect on the capillary tube communicating the sensor to the thermostatic control, it is surrounded by a sheath of highly conductive metal. This sheath ends in a tube of the same metal which can be extended by a radiator. ln this way, the conductive sheath constitutes a heat pump removing heat to the outside. The head can be protected on the inside by a layer of insulating material. The device is particularly useful for domestic gas cookers.

9 Claims, 3 Drawing Figures THERMOSTATIC CONTROL OF VESSELS SUBJECTED TO HEATING The invention relates to devices of the type for the thermostatic control of vessels or the like subjected to heating action.

In devices of this type, it happens that certain of their elements or members, other than those taking part in the thermostatic regulation, are subjected to a secondary heating action, especially to the action of a flame, although it is desirable that the temperature of these elements, for their sound operation or for the sound operation of the assembly, should not exceed a certain value.

This is the case, in particular, for devices intended for the thermostatic control of vessels or the like subject to heating action by at least one gas burner or the like, on a domestic apparatus (cooker, etc.).

These devices include for example, as described in US. Pat. No. 3,632,040 granted Jan. 4, 1972 of Applicant, a sensor intended to be positioned over a burner and to come into contact with a cooking vessel, said sensor being mounted at the end of an arm of which the other end is connected, especially in articulated manner, to the table of the apparatus bearing the burner, hence at a cold point. This arm, which serves as a guide for a capillary tube ensuring fluid or liquid communication between said sensor at one end, and a thermostatic capsule at the other end, passes through the flame of the burner, so that it is subject to a high heating effect. Since, in other respects, the temperature of the said fluid or liquid must not exceed a certain maximum value (for example of the order of 500), this may lead to the taking of special precautions, taking into account that under the direct effect of the flame the said arm can reach at the surface distinctly higher values, of the order of 700 to 800 or more.

Recourse is had, according to the invention, to a feature such, that the capillary tube is contained inside a sheath of high conductive metal, for example of copper, which sheath itself passes along or inside the above-mentioned arm, formed of a metal resistant to the physico-chemical action of the flame, for example of stainless steel.

Between the hottest zone, that is to say the zone of the flame with full gas delivery, and the cold or cool zone corresponding to the end of the arm connected to the table of the heating apparatus, the highly conductive sheath plays the role of a heat pump, tending to reduce considerably the temperature in the zone of the flame.

There may also, if necessary, be provided at the outlet of the copper sheath, at the coldest point, supplementary cooling means, for example fins.

Due to the foregoing features, the assembly operates in a correct manner, the temperature of the communicating fluid not exceeding the imposed limiting value.

It may happen however that at slow speed the flames of the burner, in becoming more compact, come to exert an interfering heating on the portion neighboring the sensor proper. This can be remedied, according to another feature of the invention, by interposing between said sensor and the head which supports it suitable heat insulators (steatite, corindon, etc.). This head could also be constituted by a material of this type (ceramic, etc.).

The invention comprises, apart from these main features, certain other features which are preferably used at the same time, and which will be more explicitly discussed below.

It relates, more particularly, to certain types of application (especially that for which it is applied to devices of the type concerned for the thermostatic control of a vessel subject to a heating action, on domestic gas apparatus), as well as to certain embodiments, of said features; and it contemplates, more particularly again, and this by way of new industrial products, devices of the type concerned including the application of the same features.

The invention will in any case, be better understood by means of the supplementary description which follows, as well as of the accompanying drawings, which supplement and drawings are, of course, given purely by way of illustrative but non-limiting example.

In the drawings:

FIGS. 1 and 2, show respectively in partial elevation, with portions in section, in a partial plane, the assembly of a sensor for a vessel to be placed above a gas burner (said vessel, in FIG. 1, not yet being placed inposition), this assembly representing one embodiment constructed according to the invention; and

FIG. 3 illustrates similarly, but laterally with respect to FIG. 1 and with the vessel placed in position, an assembly of the same type, the gas being assumed as burning at slow rate.

According to the invention and more particularly according to those of its types of application, as well as according to those embodiments of its various parts, to which it would appear that preference should be given, in order for example, on a domestic gas apparatus comprising at least one burner, to construct a sensor device for the thermostatic control of the temperature of cooking or other vessels, procedure is as follows or in similar manner.

Essentially this device is made to include the sensor proper constituted by a capsule 1 adapted to come into contact with the bottom 2 of the casserole (FIG. 3), this capsule 1 being intended to be connected to a schematically represented thermostatic capsule 21 placed at a distance (especially adapted to act on a cock), or valve (not shown), by means of a fluid passing through a capillary pipe such as 3, for example of stainless steel.

Said sensor 1 and the capillary tube 3 are borne by the assembly of a head 4 surrounding the sensor proper and an arm 5, inside which the said capillary tube passes, this arm 5 being connected, at its end opposite that bearing the head 4, to the table 6 of the domestic appliance. The arm 5 and the head 4 are, for example, constructed of metal.

In particular, according to the features of the abovementioned patent, the arm 5 can be hinged, at its cold end opposite the sensor, around a horizontal axis such as 7, which solution in particular enables the sensor be withdrawn for cleaning.

In addition, elastic means, not shown in the drawings, tend to urge the said arm in the direction which causes the maintenance of the sensor 1 in contact with stops constituted for example by the elements of a grid 8.

This contact is shown clearly in FIGS. 2 and 3. When the casseroleZ has been placed in position, the latter pushes back the assembly of the arm 5 and its sensor, or again, as shown, it only pushes back the sensor 1 which is mounted elastically, the spring being formed for example by several turns of the capillary tube 3. The burner has been shown at 9, 10.

Any other solution could, of course, be adopted.

Whatever the constructive solution selected, it is noted that the arm 5, over its course, between the head 4 and the end arranged on the side of the table 7, is brought to pass through the flame 11 of the burner, especially in the position of full delivery assumed in FIG. 1. As a result, at this place, there is a considerable heating action, the efiects of which on the capillary tube 3 it is desirable to reduce, so that the temperature of the latter does not exceed-the required limiting value, that is to say 400 to 500.

To this end, according to the invention, there are provided means for ensuring vigorous removal of heat in the directiongoing from the region of the. flame to the cold region at 7.

These means can consist for example of introducing the capillary tube 3 inside a sheath 12 of highly conductive metal, for example of copper, this sheath 12 being itself introduced inside the arm which is made hollow and which is constructed preferably of a metal resistant to the physico-chemical effect of the flame, for example of stainless steel.

The head 4, which can have any suitable shape to ensure contact with the elements of the grid 8 (for example a shape such as that shown in FIG. 3, which is a cross-sectional view with respect to the FIG. 1), can itself be formed of stainless steel, with an extension 13 ensuring fixing on the corresponding end of the arm 5.

On the side of the connection with the table 6, the arm 5 ends at the part such as 14 which, in the embodiment shown, is hinged around the axle 7. In the said part 14, the arm 5 can be continued by a copper part 15 which opens at 16, and from which a capillary tube 3 emerges towards the thermostatic capsule.

This assembly already constitutes an efficient heat pump removing calories towards the portion 16, so that the temperature of the sheath 3, in the zone of the flame, can be lowered to the minimum value sought.

However, in certain cases, it could be advantageous to complete this heat removal by the use of additional means constituted for example by radiator elements 17 arranged at the outlet, such as fins of copper brazed on the part 15.

It is self-evident also that additional heat insulating means could be provided inside the arm 5, for example between the capillary tube 3 and the copper tube 12, or between the tube 12 and the arm 5 as shown at 20, or at both these places, means such as glass wool, a steatite tube, etc.

It would be appropriate on the other hand to examine what happens when the flame of the burner operates at a slow rate.

Under these conditions, and as shown in FIG. 3, the spread of flames contracts towards the axis of the burner, thereby approaching consequently the head 4 of the sensor. A troublesome effect on the sensor could hence result therefrom.

To avoid this interfering effect, there is advantageously provided, inside the head 4, an insulating means between the walls of this head, on one hand, and the sensor proper l and its associated elements, on the other hand.

These means are formed for example by lining the inside of the head 4 by an element of a ceramic product such as steatite or corundum, as shown at 18 in FIG. 1. A metallic intermediate element 19 will be provided between the head 4 and the sensor.

But the head 4 could also be formed, not only of metal, but of a ceramic or other material, constituting heat insulation. This material could also be enameled, which could contribute to a better external appearance.

In the foregoing, there has been considered the case of a sensor of which the arm 5 was connected in a hinged manner to table 6. However, of course, the invention could be applied, in a general way, to all sensor devices, even to an arm connected in fixed manner to the table.

The foregoing features would also be applicable, in a general way, to any assemblies other than those described above, comprising an element subject to the effect of flame, which element is intended to serve as a guide to a capillary tube or any other element, the temperature of which it is desired to limit.

As a result of which, whatever the embodiment adopted, therecan be constructed feeler devices whose operation emerges sufficiently from the foregoing for it to be unnecessary to dwell further on this subject, and which have, with respect to those of the type concerned existing hitherto, numerous advantages, especially:

that of enabling the maintenance, at a suitable temperature, of the capillary tubes ensuring communication between the sensor and the thermostatic capsule,

and that nonetheless of enabling inexpensive solutions.

As is self-evident, and as emerges already from the foregoing, the invention is in no way limited to those of its types of application, nor to those of its embodiments of its various parts, which have been more especially considered; it encompasses, on the contrary, all variations.

I claim:

1. Thermostatic control device for use with a support table having heat generating means for heating vessels, said device comprising an arm arranged to traverse said heat generating means and be so exposed to a high heating effect, a temperature sensor resiliently borne at one end of said arm so that it can contact said vessel and the other end of the arm being pivotally connected to the support table, a thermostatic control fluidcontaining member connected at the other end of said arm, a capillary tube carried by said arm resiliently connecting said sensor to said thermostatic member and sealed with a fluid therein, and a sheath of highly heat-conductive metal within said arm surrounding said capillary tube and terminating at an external cold point in said support table remote from said sensor, so as to protect the capillary tube from excessive heat and conduct heat away from the sensor and capillary tube.

2. Device according to claim 1, said other end of the sensor arm being hinged around the cold point in said support table, as a flame cooker,.wherein the arm is constructed of a metal resistant to the effect of the flame.

3. Device according to claim 1, including a conductive part ending said arm and arranged on said support table connected in articulated manner at the external table cold point.

heat insulating material bearing the sensor proper 7. Device according to claim 6, wherein the head material is of ceramic.

8. Device according to claim 6, wherein the head material is enamelled.

9. Device according to claim 2, including a heat insulating material, interposed between the capillary tube and the external wall of the arm. 

1. Thermostatic control device for use with a support table having heat generating means for heating vessels, said device comprising an arm arranged to traverse said heat generating means and be so exposed to a high heating effect, a temperature sensor resiliently borne at one end of said arm so that it can contact said vessel and the other end of the arm being pivotally connected to the support table, a thermostatic control fluidcontaining member connected at the other end of said arm, a capillary tube carried by said arm resiliently connecting said sensor to said thermostatic member and sealed with a fluid therein, and a sheath of highly heat-conductive metal within said arm surrounding said capillary tube and terminating at an external cold point in said support table remote from said sensor, so as to protect the capillary tube from excessive heat and conduct heat away from the sensor and capillary tube.
 2. Device according to claim 1, said other end of the sensor arm being hinged around the cold point in said support table, as a flame cooker, wherein the arm is constructed of a metal resistant to the effect of the flame.
 3. Device according to claim 1, including a conductive part ending said arm and arranged on said support table connected in articulated manner at the external table cold point.
 4. Device according to claim 1, including a radiator member terminating, on the side of the table cold point of the assembly of the capillary tube and its conductive sheath.
 5. Device according to claim 1, including a metallic head bearing the sensor proper and joined by said arm, and a sheath of insulating material inside of the head to protect it against the effect of the heat generating means.
 6. Device according to claim 1, including a head of heat insulating material bearing the sensor proper.
 7. Device according to claim 6, wherein the head material is of ceramic.
 8. Device according to claim 6, wherein the head material is enamelled.
 9. Device according to claim 2, including a heat insulating material, interposed between the capillary tube and the external wall of the arm. 